The prior art tube bundles of high temperature heat exchangers have typically been secured to interior refractory material, adding stress to the refractory material, causing premature refractory failure and expensive repair of the refractory material and tube bundle. Designing support structures for tube bundles in high temperature heat exchangers, including reforming reactors, has been and continues to be a major problem. Support structures for use inside high temperature vessels must withstand excessively high temperatures and weight stresses while supporting a variety of components including baffles, catalyst tubes, diffusion plates and other components in extremely harsh environments.
The prior art support structures in reforming exchangers include attachment directly into the refractory material which lines the interior surface of catalytic reactors. The refractory material covers and protects the interior surface of the catalytic reactor from the high temperatures generated within the reactor and prevents "hot spots," i.e., excessive amounts of heat from reaching and possibly causing failure of the reactor walls. The refractory material can be of varying thicknesses and components, but is typically a ceramic or cement-like material which is heat resistant. Refractory material is brittle and does not adequately support interior components which may expand or contract due to the wide temperature variations.
Refractory material thus has a limited life expectancy under optimum conditions. Given the additional stresses of supporting internal components, the refractory material tends to break loose at an accelerated rate, increasing the frequency of costly repair and interrupting the operation of the exchanger. Moreover, the internal support structures supported by refractory in prior art reactors are typically constructed of various metallic alloys. When the temperatures change from cool to hot to cool again, these support structures can damage refractory during the thermal expansion and contraction cycles.
Therefore, a need exists for a tube bundle support system designed to withstand the harsh environment of the high temperature exchanger to reduce the expense and time involved in repairing and maintaining exchangers of this nature.